THz Generation and Detection on Dirac Fermions in Topological Insulators

Luo, Chih-Wei; Chen, Hsueh Ju; Tu, Chien Ming; Lee, Chia Ching; Ku, S. A.; Tzeng, Wen Yen; Yeh, Tien Tien; Chiang, Ming‐Chang; Wang, Harn Jiunn; Chu, Wei; Lin, Jiunn-Yuan; Wu, Kaung-Hsiung; Juang, Jenh‐Yih; Kobayashi, Takayoshi; Cheng, Cheng Maw; Chen, Ching Hung; Tsuei, Ku Ding; Berger, H.; Sankar, Raman; Chou, F. C.; Yang, H. D.

doi:10.1002/adom.201300221

Cited by 54 publications

(49 citation statements)

References 35 publications

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“…Therefore, it cannot arise from the initial optical transition. In fact, previous works on Bi 2 Se 3 assigned the slow J yz component to a carrier drift in the surface field, consistent with the strong dependence of J yz on the doping level of Bi 2 Se 3 (refs 9, 10, 11). This notion is further supported by additional observations made in our experiment: first, the initial electron flow is directed toward the sample surface, along the direction of the space–charge field of our effectively n-doped sample.…”

Section: Resultssupporting

confidence: 83%

“…Since the slow component of J yz is a drift current of photoexcited carriers in the space–charge field91011, it is also localized in a depth of ∼15 nm. In addition, its amplitude changes during sample aging must arise from gradual modifications of E SC (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Part of this considerable potential was demonstrated by recent works, which reported the exciting possibility of launching TI surface currents by simply illuminating the sample with light678910111213. The direction of the photocurrent could be controlled through the polarization state of the incident light beam.…”

mentioning

confidence: 99%

“…Scenarios based on asymmetric depopulation of the Dirac cone6 transitions into other higher-lying cones13, and asymmetric scattering of electrons8 have been proposed. To directly resolve the generation of TI surface photocurrents, we need to boost the time resolution of the experiment from so far as ∼250 fs and longer910111213 to the scale of elementary scattering events, which can be shorter than 10 fs.…”

mentioning

confidence: 99%

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Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

Braun¹,

Mußler²,

Hruban³

et al. 2016

Nat Commun

185

176

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Three-dimensional topological insulators are fascinating materials with insulating bulk yet metallic surfaces that host highly mobile charge carriers with locked spin and momentum. Remarkably, surface currents with tunable direction and magnitude can be launched with tailored light beams. To better understand the underlying mechanisms, the current dynamics need to be resolved on the timescale of elementary scattering events (∼10 fs). Here, we excite and measure photocurrents in the model topological insulator Bi2Se3 with a time resolution of 20 fs by sampling the concomitantly emitted broadband terahertz (THz) electromagnetic field from 0.3 to 40 THz. Strikingly, the surface current response is dominated by an ultrafast charge transfer along the Se–Bi bonds. In contrast, photon-helicity-dependent photocurrents are found to be orders of magnitude smaller than expected from generation scenarios based on asymmetric depopulation of the Dirac cone. Our findings are of direct relevance for broadband optoelectronic devices based on topological-insulator surface currents.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

Braun¹,

Mußler²,

Hruban³

et al. 2016

Nat Commun

185

176

View full text Add to dashboard Cite

show abstract

“…However, while most of the researches have been concentrated on the thermoelectric [13] and optoelectronic properties [14,15], researches on the mechanical characterizations have not drawn equal attention. The mechanical properties of materials are sizedependent.…”

Section: Introductionmentioning

confidence: 99%

Nanomechanical properties of Bi2Te3 thin films by nanoindentation

Tasi

Tseng

Jian

et al. 2015

Journal of Alloys and Compounds

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Nonlinear Optics with 2D Layered Materials

et al. 2018

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2D layered materials (2DLMs) are a subject of intense research for a wide variety of applications (e.g., electronics, photonics, and optoelectronics) due to their unique physical properties. Most recently, increasing research efforts on 2DLMs are projected toward the nonlinear optical properties of 2DLMs, which are not only fascinating from the fundamental science point of view but also intriguing for various potential applications. Here, the current state of the art in the field of nonlinear optics based on 2DLMs and their hybrid structures (e.g., mixed-dimensional heterostructures, plasmonic structures, and silicon/fiber integrated structures) is reviewed. Several potential perspectives and possible future research directions of these promising nanomaterials for nonlinear optics are also presented.

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THz Generation and Detection on Dirac Fermions in Topological Insulators

Cited by 54 publications

References 35 publications

Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3

Nanomechanical properties of Bi2Te3 thin films by nanoindentation

Nonlinear Optics with 2D Layered Materials

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